Temperature-dependent optical properties of Intralipid® measured with frequency-domain photon-migration spectroscopy

Abstract

Abstract. We present the temperature dependence of absorption and reduced scattering coefficients of 1.8% Intralipid measured by frequency-domain photon-migration spectroscopy between 710 and 850 nm. These measurements were made in the physiologically relevant 30 to 40°C temperature range. The temperature coefficients for absorption were consistent during heating and cooling and follow closely other reported results. The change in absorption coefficient at 740 nm suggests that a minimum temperature change of 4°C is observable within the error limits. We found that the reduced scattering coefficient shows a hysteresis with temperature at 740 nm. The temperature coefficient for reduced scattering determined from heating cycle measurements agrees with theory and other measurements within the error limits.

Dependence of optical scattering from Intralipid in gelatin-gel based tissue-mimicking phantoms on mixing temperature and time

“…Right before measurements of both diffusivity and particle size, these samples were remixed to ensure sample homogeneity. The measured μ 0 s from all these samples was between 9.0 and 11 cm −1 , confirming the previous reports 25,31 on the diffusivity of Intralipid-water samples. Figure 8(a) is an example of a lipid droplet size distribution histogram measured by the DLS method.…”

“…Further investigation can clarify this matter, but is outside the scope of this paper. To fabricate Intralipid-gelatin-water phantoms having optical diffusivity that is consistent with that of Intralipid-water counterparts, 25,31 we found it is crucial to maintain the mixing temperature below 37°C and use mixing times not exceeding 2 h. We recommend our modified protocol for making Intralipid-gelatin-water phantoms for future optical experiments.…”

“…32 Second, the refractive index of water changes with the measured temperature, 33 which alters the mismatch of refractive index between the Intralipid particles and the water, and introduces variations in μ 0 s . 31 In Fig. 5, we presented the measured μ 0 s from the solidified Group 2 samples at room temperature.…”

“…Note that the absorption due to 1% Intralipid is negligible. 31 Therefore, once Δx was determined from the sample's reflectance pattern, as shown in Fig. 3, the reduced scattering coefficient can be calculated by…”

Industrial applications of Photon Density Wave spectroscopy for in-line particle sizing [Invited]

“…For turbid liquid dispersions, Photon Density Wave (PDW) spectroscopy [1][2][3] provides this fundamental benefit. Recently, this technology was further developed to demonstrate its applicability to the monitoring of chemical or physical processes within liquid turbid systems [4][5][6][7].…”